REV.

OP777/OP727/OP747

–10–

TEMPERATURE – C

14.944

60

40

140

20 0

20 40

60

80 100 120

14.946

14.948

14.950

14.954

14.956

14.958

14.960

14.962

14.964

14.952

TPC 46. Output Voltage High vs.

Temperature

TEMPERATURE – C

14.960

60

40

140

20

0

20 40

60

80 100 120

14.955

14.950

14.945

14.935

14.930

14.940

TPC 47. Output Voltage Low vs.

Temperature

TIME – Minutes

1.5

0

1.5

0

0.5

5.0

1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

1.0

0.5

0.5

1.0

TPC 48. Warm-Up Drift

BASIC OPERATION

The OP777/OP727/OP747 amplifier uses a precision Bipolar

PNP input stage coupled with a high-voltage CMOS output

stage. This enables this amplifier to feature an input voltage

range which includes the negative supply voltage (often ground-

in single-supply applications) and also swing to within 1 mV of the

output rails. Additionally, the input voltage range extends to within

1 V of the positive supply rail. The epitaxial PNP input structure

provides high breakdown voltage, high gain, and an input bias cur-

rent figure comparable to that obtained with a “Darlington” input

stage amplifier but without the drawbacks (i.e., severe penalties for

input voltage range, offset, drift and noise). The PNP input structure

also greatly lowers the noise and reduces the dc input error terms.

Supply Voltage

The amplifiers are fully specified with a single 5 V supply and, due

to design and process innovations, can also operate with a supply

voltage from

V up to 30 V. This allows operation from most

split supplies used in current industry practice, with the advantage

of substantially increased input and output voltage ranges over

conventional split-supply amplifiers. The OP777/OP727/OP747

which is most suitable for single-supply application. With PSRR of

130 dB (0.3

μV/V) and CMRR of 110 dB (3 μV/V) offset is mini-

mally affected by power supply or common-mode voltages. Dual

supply,

±15 V operation is also fully specified.

Input Common-Mode Voltage Range

The OP777/OP727/OP747 is rated with an input common-mode

voltage which extends from the minus supply to within 1 V of the

positive supply. However, the amplifier can still operate with input

configured as a difference amplifier with a single supply of

V

and negative dc common-mode voltages applied at the inputs

terminals. A 400 mV p-p input is then applied to the noninverting

input. It can be seen from the graph below that the output does not

show any distortion. Micropower operation is maintained by using

large input and feedback resistors.

+3V

OP777/

OP727/

OP747

100k

100k

100k

100k

0.1V

0.27V

Figure 2. OP777/OP727/OP747 Configured as a Differ-

D

3.0

3.0

TIME – 0.2ms/DIV

0V